What Happened in Vegas?

The adorable pair sing hits from their album Cheek to Cheek during their New Year's Eve performance at The Cosmopolitan of Las Vegas.

Pop princess Britney Spears was the guest of honor at a massive gala event held at The LINQ Promenade in Las Vegas on Nov. 5, 2014. The singer, who headlines at the Planet Hollywood Resort & Casino with her resident show Britney: Piece Of Me, was given the ceremonial Key To The Las Vegas Strip. Clark County Commission Chairman Steve Sisolak presented the honor, and proclaimed that Nov. 5 be "Britney Day."

Stand-up comic Lisa Lampanelli, famous for her biting brand of insult comedy and truly raunchy humor, joined the all-female comedy series 'Lipshtick –The Perfect Shade Of Stand-Up', an on-going stand-up showcase at The Venetian in Las Vegas. Lampanelli, who has performed at 'Lipshtick' once before, took the stage on Friday and Saturday in the Sands Showroom.

One Direction's Niall Horan, singer Ed Sheeran, and rapper Macklemore partied together the XS Nightclub in Las Vegas. The trio drank and danced while DJ superstar David Guetta rocked the club.

Nick Jonas celebrated his solo debut and the release of his new single "Chains" at XS nightclub in Las Vegas. Zedd was at XS for his set, and he chatted with Nick before posing for this photo. The Jonas Brothers first visited XS to celebrate Nick's 21st birthday.

Britney Spears returned to the stage of The AXIS Powered by Monster at Planet Hollywood Resort & Casino on Aug. 15, 2014 for her Britney: Piece of Me show. In the crowd Friday night were Miss USA Nia Sanchez and Miss Teen USA 2013 Cassidy Wolf. The girls went backstage before the show to greet Britney and take a photo with her.

Dancing with the Stars power couple Kym Johnson and Carson Kressley took a spin on the High Roller after taking in Olivia Newton-John's show at Flamingo Las Vegas. This was all before they headed over to Rio All-Suite Hotel & Casino to see the Chippendales.

Khloe Kardashian celebrated her birthday on America's birthday! The Keeping Up with the Kardashians star, who turned 30 on June 27, 2014, hosted a massive party on the Fourth of July in Las Vegas.

Khloe partied with friends, fans and her boyfriend, rapper French Montana, in the City of Sin. The group kicked off their wilder festivities at Tao Nightclub, where she was presented with her 30th birthday cake in the traditional Vegas style -- by two hot showgirls in feather headdresses and an Elvis impersonator.

The 19th Lingerie Fighting Championships were held at the Silver Nugget Casino Event Center in North Las Vegas on May 30. Here, combatants Lauren 'The Animal' Erickson, in black, and Robyn 'Ruthless' Hawkins, in pink, battle it out. Erickson ended up winning the bout.

Celebrity Chef Gordon Ramsay, best known for his shows Hell's Kitchen and Kitchen Nightmares, cooked up tasty meals at his BurGR booth at Vegas Uncork'd, an event presented by Bon Appetit at Caesars Palace that brought all the greatest celebrity chefs, who own restaurants on the strip, to one massive Grand Tasting, which ran from May 8 to May 11. Ramsey's BurGR joint can be found at Planet Hollywood Resort and Casino.

Hip hop superstar Kendrick Lamar performed some of his hit songs, like Backseat and m.A.A.d City, at REHAB, the poolside dayclub at the Hard Rock Hotel and Casino, on May 3.

Jax Taylor and Tom Sandoval, stars of the Bravo TV reality series Vanderpump Rules, partied hard at Hyde Bellagio in Las Vegas on Saturday, April 26, 2014. The reality stars posed on the red carpet outside the club before going inside for a night of drinking, dancing and partying with friends and fans.

Boxers Manny Pacquiao and Timothy Bradley stepped into the ring for the first time against each other since their June 2012 bout where Bradley scored a close and controversial win over Pacquiao. After a solid match this time around, Pacquiao managed to reclaim his WBO welterweight title in a decisive victory at the MGM Grand Garden Arena in Las Vegas on April 12.

Nick Jonas, formerly of the band The Jonas Brothers, hit up Sin City and partied at the XS nightclub, where he hung out with DJ Diplo and partied the night away, April 5.

Everybody Loves Raymond star Ray Romano took a swing at competing in the 13th annual Michael Jordan Celebrity Invitational hosted by the Aria Resort and Casino at the Shadow Creek Golf Course on April 6.

Music legend Sir Elton John and his partner David Furnish celebrate Elton's 67th birthday at the Grand Opening of the champagne lounge Fizz inside Caesars Palace on March 28. Furnish is also the creative director of Fizz.

Reality TV star Brody Jenner got down and partied hard with close friends in a wild night of bottle service and dancing at the exclusive nightclub Hyde Bellagio, where some gorgeous servers welcomed the former The Hills star with giant letters spelling out his name. The alcohol and confetti-filled partying went on into the early hours of the morning.

Red headed Comedian Carrot Top and Motley Crue singer Vince Neil hung out with NASCAR driver Carl Edwards and his #99 Aflac Ford Fusion before the start of the Kobalt 400 at the Las Vegas Motor Speedway on March 9.

Backstreet Boys member Nick Carter and his fiancée Lauren Kitt celebrated their upcoming wedding with a co-ed Bachelor and bachelorette party at the Palms Casino in Las Vegas. They partied with their close friends, groomsmen and bridesmaids at the Ghostbar, where Lauren fed Nick a diamond ring topper off their congratulatory cake.

Britney Spears performs at the sold-out debut of her Las Vegas residency show Britney: Piece of Me at Planet Hollywood Resort & Casino on Friday, December 27.

Miley Cyrus and Kellan Lutz attend the launch of the Las Vegas return of Beacher's Madhouse at MGM Grand Hotel & Casino on Friday, December 27.

Miley Cyrus attends the launch of the Las Vegas return of Beacher's Madhouse at MGM Grand Hotel & Casino with Katy Perry on Friday, December 27.

Bruno Mars poses with cast members of the hit musical Jersey Boys after attending a production of the musical at Paris Las Vegas on December 5.

Actress and singer Selena Gomez performed at the Mandalay Bay Events Center in Las Vegas on November 9. She is touring in support of Stars Dance, her debut album released in July.

Newly engaged Kim Kardashian celebrates her 33rd birthday with fiancé Kanye West at TAO at The Venetian in Las Vegas on Friday, October 25.

Reality TV celebrity Kim Kardashian celebrates her 33rd birthday with sisters Kourtney and Khloe and mother Kris at TAO at The Venetian in Las Vegas on Friday, October 25.

Kim Kardashian poses with an extravagant cake as she celebrates her 33rd birthday at TAO at The Venetian in Las Vegas on Friday, October 25.

Paris Hilton throws a birthday party for her sister Nicky at XS Nightclub in Las Vegas on her 30th birthday on October 5.

Paris Hilton throws a birthday party for her sister Nicky at XS Nightclub in Las Vegas on her 30th birthday on October 5.

Model Kate Upton enjoys a fun night out in Las Vegas on September 26 as she parties at Hakkasan Las Vegas at MGM Grand Hotel & Casino.

Model Kate Upton enjoys a fun night out in Las Vegas on September 26 as she parties at Hakkasan Las Vegas at MGM Grand Hotel & Casino.

After performing at the iHeartRadio Music Festival in Las Vegas on Friday, Sept. 20, Katy Perry meets up with a group of 50 of her friends, including actress Kate Hudson, at XS Nightclub.

Nick Jonas and his girlfriend, Miss Universe 2012 Olivia Culpo, celebrate his 21st with a toast of champagne for his first legal sip of alcohol and a kiss on September 16.

Nick Jonas celebrates his 21st birthday with Miss Universe girlfriend Olivia Culpo at XS The Nightclub at Encore Las Vegas in the early hours of September 16.

Nick Jonas poses with his tower cake for his 21st birthday at Botero at Encore Las Vegas on September 16.

"Blurred Lines" singer Robin Thicke poses for a photo with his fans as he performs at Ditch Fridays at the Palms Casino Resort in Las Vegas on September 13.

"Blurred Lines" singer Robin Thicke poses for a photo with his fans as he performs at Ditch Fridays at the Palms Casino Resort in Las Vegas on September 13.

Country music star Lorrie Morgan sang at the Smith Center for the Performing Arts in Las Vegas as part of her Grits and Glamour tour on September 7.

Rapper and actor LL Cool J gets playful with the crowd during a performance at Palms Casino Resort on Saturday, September 1.

Rapper Kendrick Lamar kicks off the Labor Day weekend with a concert at Palms Casino Resort on Friday, August 30.

Singer Ashanti enjoys the view from up above at Palms Casino Resort before a 45-minute performance at Moon Nightclub later that night on Friday, August 30.

Breaking Bad actor RJ Mitte celebrates his 21st birthday at Palms Casino Resort in Las Vegas with actresses Amanda Fuller and Lindsay Haun on August 23.

Reality star Brody Jenner celebrates his upcoming 30th birthday with a party at Hyde Bellagio in Las Vegas on August 17.

After being bailed out of jail for $1 million and while currently facing prison time for fraud charges, Teresa and Joe Giudice are not shying away from the public eye. The Real Housewives of New Jersey stars showed up for an appearance at Las Vegas' Hard Rock Hotel and Casino, and Teresa was quick to throw up lots of pics from the weekend on her Instagram. She captioned one photo: "Me and my Juicy Joe."

Ne-Yo returns home to his old stomping grounds, Las Vegas, for a concert at Palms Pool for "Ditch Fridays" on August 9.

On-screen mother-daughter combo Sharon Stone and Amanda Seyfried share a candid moment as they premiere their biopic Lovelace in Las Vegas on Sunday, August 4.

After watching the Absinthe show at Caesars Palace in Las Vegas, actor Neil Patrick Harris tries to the tightrope for himself with the aid of Tony "Tightropes" Hernandez, brother-in-law of Grand Canyon tightrope walker Nik Wallenda.

Jordan Knight, Jonathan Knight, Donnie Wahlberg, and Danny Wood (left to right) of boy band New Kids on the Block make a toast at PURE Nightclub at Caesars Palace in Las Vegas on July 6.

Pop rock band Hot Chelle Rae ("Tonight Tonight," "I Like It Like That"), which is currently on tour with Justin Bieber, soaks up the Las Vegas sun as they pose for a photo poolside at the Hard Rock Hotel & Casino Las Vegas on June 28.

Reality TV star Kendra Wilkinson-Baskett celebrates her 28th birthday with an colorful cake at Chateau Nightclub & Gardens in Las Vegas on Saturday, June 15.

Donald Trump and Miss Universe Olivia Culpo pose together on the red carpet of Las Vegas nightclub The ACT on Saturday, June 15.

Miss USA Nana Meriwether and Miss Alabama Katherine Webb pose together on the red carpet of Las Vegas nightclub The ACT on Saturday, June 15.

Illusionist Criss Angel takes a photo with hip-hop artist Ludacris before he takes the stage at a concert at the Palms Casino Resort in Las Vegas on June 7.

Katrina Bowden and Audrina Patridge show off their Simon G. jewelry at the Simon G. soiree at TAO Las Vegas on June 1.

Sean "Diddy" Combs hosts and performs at a concert at Rehab day-club with Lil Wayne and Meek Mill on Sunday, May 26.

Covered in blue attire, actress Elizabeth Banks spends some quality relaxation time at Azure Luxury Pool at The Palazzo Las Vegas over the Memorial Day weekend.

Breaking Bad star Aaron Paul and his fiancée Lauren Parsekian celebrated their upcoming nuptials by partying the night away at Marquee's Library Room with a large group of friends on Saturday, May 18 in Las Vegas, Nevada.

Singer Miguel headlined the MAXIM Music Weekend at TAO Nightclub in Las Vegas, Nevada, on Saturday singing his hits Sure Thing and Adorn prior to hitting the Billboard Music Awards stage Sunday night.

Holly Madison flaunts her post-pregnancy body at the season opening of TAO Beach on Saturday, May 4.

Carmen Electra poses with her cake as she celebrates her 41st birthday at Crazy Horse III Gentleman's Club on Saturday, May 4.

How I Met Your Mother actor Neil Patrick Harris enjoys a night out at Hakkasan Las Vegas as Grammy-winning DJ Calvin Harris performed on Saturday, May 4.

Rumer Willis was joined by boyfriend Jayson Blair at TAO Las Vegas' Marquee Dayclub season opening where they celebrated a friend's birthday.

British singer-songwriter Rita Ora bumped into 90210 star Jessica Lowndes while hosting a dinner at TAO Nightclub on March 30.

Stacy Keibler hosted Dom Perignon's Halloween Masquerade at Hyde Bellagio on October 27.

Eva Longoria and Dania Ramirez started their own private dance party at TAO nightclub on September 29.

Jack Osbourne and friends kicked off their guys' weekend at the Azure Pool at The Palazzo on September 22. It wasn't your average bachelor party, as Osbourne refrained from drinking, but he did dine on Oktoberfest treats, including Munich brat and potato salad.

Grammy-winning dancehall star Sean Paul performed at the Rehab Sunday Pool Party inside Hard Rock Hotel & Casino in Las Vegas on September 16.

Boxing sensation Saul 'Canelo' Alvarez celebrated his win over Josesito Lopez on September 15 at LAX Nightclub inside Luxor Hotel and Casino.

Chris Brown dressed to impress at 'The Sexiest Party in the City,' thrown by Sean 'Diddy' Combs over Labor Day weekend at Chateau Nightclub & Gardens.

Metta World Peace (formerly known as Ron Artest) chowed down at Sugar Factory American Brasserie at Paris Las Vegas on August 25.

Olympic champion swimmer Ryan Lochte shows off his patriotism and abs at Tao Beach over the weekend.

Ryan Lochte turned 28 on August 3, but he held a belated birthday celebration poolside at Azure at The Palazzo on August 18.

Lochte capped off the night at LAVO.

Jennifer Lopez lounged poolside at Wet Republic at MGM Grand in Las Vegas on Saturday, August 18 for a pre-party to celebrate her world tour with Enrique Iglesias.  

LL Cool J sprayed partygoers at the Hard Rock Hotel & Casino with a Beachlife water gun on May 20.

Playboy Playmate of the Year, Claire Sinclair, celebrated her 21st birthday at Crazy Horse III Gentlemen's Club and Posh Boutique Nightclub on May 26.

Ice-T and Coco were spotted poolside at Venus Pool Club at Caesars Palace before hitting up LAX Nightclub on May 26.

Jennifer Lopez and boyfriend Casper Smart celebrated J.Lo's single Goin' In at Hyde Bellagio in Las Vegas on May 26. Later, J.Lo left the VIP area to join DJ Mick Boogie in the DJ booth.

Kelly Osbourne confronted her biggest fear at the annual Couture show in Vegas on June 2. The singer/actress, made friends with a sparkly Palladium spider broach.

Kelly Rowland hosted Vegas Magazine's 9th anniversary party at Boulevard Pool at the Cosmopolitan on June 9 where she performed her hit single Motivation. She was joined by LaLa Anthony.

The NHL's newest champions, the Los Angeles Kings, continued to celebrate their Stanley Cup win by partying at Hyde Bellagio on June 15.

Celebrity Apprentice star Aubrey O'Day hosted the Hard Rock Hotel & Casino's infamous pool party, Rehab Sundays on June 17.

Nicole Scherzinger celebrated her upcoming 34th birthday at TAO on June 22.

Nick Cannon picked out some his and hers outfits for his twins at Sugar Factory on June 22.

Kendra Wilkinson-Baskett celebrated her 27th birthday at PURE Nightclub with her husband Hank Baskett on June 22.

Paula Abdul celebrated turning 50 at the Planet Hollywood Resort & Casino on June 29 in a beautiful Valentino creation.

R&B star Jason Derulo and his former American Idol girlfriend Jordin Sparks arrived hand-in-hand for Derulo's live performance at PURE Nightclub inside Caesars Palace on July 7.

Mike "The Situation" Sorrentino had a belated birthday party at Senor Frog's on July 14. The Jersey Shore star turned 30 on July 4.